Aren't you putting the horse before the cart ?
First find the potential clients who aren't getting the services they need. Ask them to identify in writing what their needs are both in terms of volume, frequency and seasonal terms.
Once you have a potential cargo identified by clients as opposed to your wish list, then you can go to a financier and say "Here is a need and I know how to solve it if you fund me"
Go look for clients first.
Secondly look for the operator of an IFR twin who only uses it by day and ask what they'd say to you using it by night ?
Remember too that you need to factor in scheduled maintenance when your sole aircraft is not available. So now we're talking at least two aircraft.
How about cut flowers from Holland to UK ?
Very seasonal though. Seafood is always lucrative. Fish from Santander to wherever they want fish ?
Gotta find the need first and then satisfy it. I don't think you're ready yet because you haven't thought it through far enough. harsh thing to say but you need to go through about five drafts of this business plan before you're ready. You need failure to sharpen your pencil because once you're up and flying with loans to repay it's too late to find you haven't done the homework.